MikePepler
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The Brand New Stihl MSA 220 C-B Cordless Chainsaw
MikePepler commented on Steve Bullman's record in News
I wonder if Husqvarna will produce a new version of theirs too? I got a 536LiXP about a year and a half ago, picking that because it had a higher chain speed (20 m/s) and cheaper batteries than the equivalent Stihl, but this new Stihl is 24 m/s chain speed and also a full-chisel chain. -
Thanks for reading, I don't get much time to post on it at the moment... Yes, used the battery husky for 99% of the coppicing last winter. Slower than the petrol but quieter and no exhaust fumes to inhale! ?
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Certainly, feel free to start one and tag me in it. ?
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Sorry, all motors have windings (or coils). It's the flow of current through these that generates the fluctuating magnetic fields that 'push' against the fixed fields of the permanent magnets in a brushless motor. The electronics are to sense the rotor position, back emf, etc. and switch the current in the windings to make the rotor spin. If you're sure you've found something different, please post a link to some technical details. Just saying it exists isn't enough I'm afraid.
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As far as I'm aware, 'digital motor' is a marketing term invented by Dyson. All brushless motors are electronically controlled. There's a good explanation here https://en.wikipedia.org/wiki/Brushless_DC_electric_motor On the other points, unless a motor uses superconducters (which require liquid nitrogen cooling) then they will never be 100% efficient, and the losses will be through heat due to resistance in the windings. When I'm not in the woods my day job is in renewable energy, and I previously worked in electronic engineering, so I do have some experience in this.
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OK, but even if that's the case, 100% efficient is still only 10% more than with current motors. Then after that you need more juice from the battery to get more power.
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Sure, but if efficiency is already 90%, there's not much room left for improvement - you can never quite get to 100%, as some of power is always lost as heat in the motor windings. I'd expect the main improvements to be around making the motors smaller and lighter. I think we'll be waiting a while anyway, husqvarna have updated their saw already but it doesn't look much different...
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Well, brushless DC motors are already 80-90% efficient, so while there's some room for improvement you're still going to need better batteries (in terms of kWh capacity, discharge current, weight, and volume) to get more kW of power delivered to the chain. But there's improvements every year, and I assume the manufacturers could put better cells into the existing battery casings so they'd be compatible with existing chainsaws.
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You need a better battery too, to provide the capacity for a more powerful motor.
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Depends on the value you put on not breathing in carbon monoxide, particulates and unburned petrol ? But I agree, there is still some way to go before battery saws can do all the jobs required.
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My view is that charging time isn't too important, it's the cost. I can't charge a battery in the woods anyway, so have two, then charge them at my leisure at home. But you then end up spending quite a bit on batteries. Maybe if there's ever a reasonably priced electric 4x4 then charging from it in the woods might be feasible. Charging from an inverter on a petrol/diesel engine would be very inefficient.
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Yes, I think so. Tesla cars are already faster than any petrol car for the same money, and are coming down in price. I've driven a BMW i3, and the experience is great. E-bikes are potentially even better though, you feel like you have bionic legs! I had an early model 10 years ago, would like to buy one again soon... All these developments should fed through to the chainsaws - e-bikes are quite similar in terms of batteries and motors. I guess the chainsaw manufacturers might take a while to do new models though, I guess they'll want to earn some cash from the existing designs first. For the chainsaw, the only points that annoy me are the lower power (I'd rate it equivalent to a 30cc saw) and the low-profile chain/bar they sell it with. But for me these are outweighed by the plus sides most of the time. I realise this thread has gone quite some way off the original topic! ?
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I coppiced about 40m3 (stacked volume) using the battery saw this winter, and it stood up to that OK. I do look forward to the day when they can get a bit more power out of them though. I think the limitation at the moment is the battery - there are plenty of compact electric motors that can deliver several kW, but they'd drain the battery too fast and reduce its cycle life too. Maybe the battery tech will move on over the next few years, seeing as the electric car sector is growing so fast.
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Yeah, you can't see the curvature in the tree there, and there wasn't much in this one. Anyway, I made the video to show a battery saw felling a tree, rather than as a tree felling demo. Battery life has been very good actually, I've got two 9Ah batteries, and not yet managed to empty them both while coppicing, though that's allowing for time spent splitting and stacking wood, moving brash, etc. Logging is probably a better test, and I've found filling a 1m3 trailer uses about 3/4 of a battery - sometimes more, sometimes less, depending on log length and how hard the wood is.
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I know it's best to cut as low as possible, but I find the curvature and thickening at the base of chestnut stems annoying when I'm processing them later for firewood (which is what most of the wood is used for, and I use a Truncator for processing), so I tend to cut a little bit higher and leave the chog behind. Is there any reason not to? Happy to improve my knowledge if so. I stopped having fires about 10 years ago, saves time and avoids breathing in lots of smoke and killing the seeds in the ground where the fire would have been. I've seen wrens, robins and mice making good use of the brash piles I've left instead.
